Cellulose-ether solvent and composition



Patented @ct. 9, i923.

UNHT stares Iran ai s-n.-

WILL R. WEBB, OF ROCHESTER, NEW YORK, ASSIGNOB TO EASTMAN KODAK OOM PANY, OF ROCHESTER, NEW YORK, A CORPORATION NEW YORK.

No Drawing. r Application filed April 5,

Toall whom it may comer-n. I

Be it known that 1, WILLIAM R. WEBB, a cit zen of the United States of America, IBSldlIlg at Rochester, in the county of Mom roe and State of New York, have invented certain new and useful Improvements in Cellulose-Ether Solvents and Compositions, of which the following is a full, clear, and exact specification.

This invention relates to solvents for.

other object of my invention is to provide a cellulose ether solution which may be manufactured into strong, 'flexible, transparent film on the machines and bythe methods now in use. T I

y In U. S. Patent No. 1,188,376, Lilienfeld June 20, 1916, there are disclosed a series of alkyl ethers, of cellulose. Certain of these are practically insolublinwater, and my invention relates but is not limited to the such as may be used in the manufacture of photographic fihn base by the customary methods, and in other plastic arts.

I have discovered that strong and useful solvent-may be prepared by mixing ethyl benzoate with one or more of the lower monohydroxy aliphatic alcohols. By the latter term'I include the members containing less than six carbon atoms.- VVhile they may be mixed in varying proportions, it is nhted,by way of example, that a useful solvent can be formed by mixing equal parts by weight of ethyl'benzoate and ethyl alcohol or methyl alcohol, or a mix-' ture of such alcohols. The'amount of ether dissolved in the solvent can be varied to suit the needs of the manufacturer; but, for puran adequately OELLULOSE-ETHER SOLVENT AND COMPOSITION.

1921. ,Serial No. 458,749.

' dissolving 1 part ofiwater-insoluble ethyl cellulose in 5 parts by weight of the above.

solvents. Other substances which. impart additional suppleness, or incombus tibility,or other qualities, to thefilm may then be added to the dope, such, for instance, as triphenyl or trlcresyl phosphate, camphor, etc. Due to its relatively low volatility, considerable amounts of the ethyl benzoate remain in the film after evaporation of the more volatile alcohols. It imparts useful properties to the film. Since the ratio of the weight of ethyl benzoate to the weight, of thecellulose greater proportion of ethyl benzoate will be present in the finished film than when the ether can be made much greater by the use of my compound solvent, instead of using. ethyl benzoate alone, it follows that a much cellulose .ethers are dissolved in ethyl benzoate as the sole solvent;

The ingredients are of the ordinary com-.

mercial type and sufliciently purified for the process of film manufacture, soas to give a dope yielding film having the proper relative freedom from color. The viscous-flowable do e above described can beused in connectlon with the usual film-forming apparatus without the necessity of expensive alterations in the latter. 4

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

'1. A viscous'flowable film-forming composition, comprising an ether of cellulose dissolved in a mixture of ethyl benzoate and a lowermonohydroxy aliphatic alcohol.

2. A viscous flowable film-forming composition, comprising an alkyl ether ofcellulose dissolved in a compound solvent containing approximately equal parts by weight of ethyl benzoate and methyl alcohol. 1

3. As an article of manufacture, a tran's parent flexible film. comprising water-insoluble ethyl cellulose and ethyl benzoate, the proportion of ethyl benzoate corresponding to a solution of the said ethyl cellulose in a compound solvent of ethyl benzoate and a-lowor m'onohydroxy aliphatic alcohol and exceeding theproportion corresponding to a solution of ethyl cellulose in ethyl benzoate 

